Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Em qual temporada regular foi 2013?
 ###Tabelas: CREATE TABLE year-by-year (year-by-year_id AUTO_INCREMENT PRIMARY KEY, Year INT, Division VARCHAR, League VARCHAR, Regular Season VARCHAR, Playoffs VARCHAR, U.S. Open Cup VARCHAR, Avg. Attendance VARCHAR) CREATE TABLE sources_of_income (sources_of_income_id AUTO_INCREMENT PRIMARY KEY, Region VARCHAR, Employment ( salaries & wages) VARCHAR, Self employed VARCHAR, Investment income VARCHAR, Working tax credit VARCHAR, State pensions VARCHAR, Occupational pensions VARCHAR, Disability benefits VARCHAR, Other social security benefits VARCHAR, Other income sources VARCHAR) CREATE TABLE g (g_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Position VARCHAR, Number INT, School/Club Team VARCHAR, Season VARCHAR, Acquisition via VARCHAR) CREATE TABLE berkhamsted (berkhamsted_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Faith VARCHAR, Type VARCHAR, Opened INT, Intake INT, DCSF number INT, Ofsted number INT) CREATE TABLE 2002_fixtures_and_results (2002_fixtures_and_results_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Competition VARCHAR, Venue VARCHAR, Result VARCHAR, Score VARCHAR, Goals VARCHAR)  
SELECT Regular Season FROM year-by-year WHERE Year = 2013